Gas purification system



Oct. 10, 1944. J. LOUMIET ET LAVIGNE 2,350,063

GAS PURIFICATION SYSTEM Filed March 20, 1941 4 SheetsSheet 1 INVENTOR.

JEAN LOUN!IET ET I AVIGNE BY2 .w/z

AT TO R N E Y:

Oct. 10, 1944 J. LOUMIET ET LAVIGNE GAS PURIFICATION SYSTEM 4 ShetsSheetFiled March 20, 1941 FIG.

, INVENTOR. JEAN LOUM|ET ET l AVIGNE BY z m g /i ATTORNEYJ 1944- J.LOUMIET ET LAVIGNE 2,360,065

GAS PURIFICATION SYSTEM Fi1d March 20, 1941 4 Sheets-Shet 5 FIG. .3.

INVENTOR. JEAN LOUMIET ET LAVIGNE ATTORNEY6 1944- J. LOUMIET ET LAVIGNEv 2,360,055

GAS PURIFICATIONSYSTEM Filed March 20, 1941 4 SheetsSheet 4 Invenm: JEANLOUMIET ET LAVIGNE Hwngy.

Patented Oct. 10, 1944 GAS PURIFICATION SYSTEM Jean Loumict et Lavigne,Itab0, Cuba Application March 20, 1941, Serial No. 384,364

In Cuba April 4, 1940 11 Claims.

The employment of centrifugal separators for the purification of vaporsor gases from particles of small size, either solid or liquid, that theyentrain is known; one form being illustrated in my previous inventiondisclosed in United States Patent #2,015,076. Al] such separatcrsoperate by causing the gas or vapor to circulate at great velocityinside a curved conduit, generally of helicoidal shap, where under theclassifying action of centrifugal force the denser particles are locatedat the outer margin of the section of the conduit, being in that wayseparated from the principal stream of gas or vapor. Afterwards theimpurities are extracted from such outer margin of the section, throughtubes that convey them to chambers where they arc deposited, when theyare solid, or to traps permitting their evacuation, when they areliquid, without permitting Waste of the gas or of the Vapor.

The technic of these separaticns was improved by my separator, since itsnormal section presents, at its outer margin where the impurities arelocated, a restricted trough which collects them; and the evacuation iseffected through extraction tubes that are connected tangentially tosaid restricted trough, so that inertia acts With full intensity todischarge the impurities into said collecting tubes.

Moreover, at the entrance of an extraction tube the restricted troughcollecting the impurities to be removed is totally or partiallyobstructed by a diaphragm or vane preierably inclined to the radius ofcurvature of the conduit, so as to defiect the impurities collected bythat restricted troug h toward the extraction tube. This arrangementimproves in practice tlie saparation operation; but it has theinconvenience of increasing the resistan which the conduit pre sents tothe motion of the circulating fluid, and in consequence increases alsothe loss of pressure required by the operation.

The several arrangements, the total or partial application of whichconstitutes the process of the invention, have for their object toimprove the result of the separation effected inside of all suchcentrifugal separators. Such a new process will be described in itsapplication to the separater of my invention; but it is, of course, alsocapable of being applied to any other centrifugal separator operating inthe way previcusly described.

The first improvement which the process of the invention introducesconsists in extracting through the extraction tube, simultanecusly withthe impurities separated in the restricted trough, a part of the gas orvapor circulating in said restricted trough. The advantages of thismethod are based on the discovery that when impurities alone arewithdrawn the fluid passing the point of withdrawal develops localdisturbances which interfere with the removal of the impurities; but,when a small portion of the fluid is withdrawn With the impurities, thefluid fiow in the main channel tends to assist such withdrawal.

The process theref0re improves considerably the results of eachseparation that the separator efiects, and makes it possible to obtain agreater purification With a much smaller apparatus and also With muchsmaller loss of pressure in the treated fluid. It has however theinconvenience of separating from the main stream a part of the fluiditslf at the same time as its impurities; but if it is considered thatwhen operating on a fluid stream of great volume, that is, Withseparators of great dimensions, the quantity of the material divertedwith the impurities does not to the loss of pressure, even if it maybecome more considerable, it only afiects a small part of the divertedmaterial, and in consequence, in terms of loss of mechanical work, itrepresents a much smaller quantity than the saving effected in the mainsupply.

In practice, the outfiow through the extraction tube of the fluid whichfills the restricted trough is secred by maintaining a lower pressure inthe deposit chambers for the impurities than the pressure inside thecoil. The pressure in the coi] is, in turn, slightly variable along thesaine, so that the sucticn toward the deposit chamber for the impuritiesproduced by that difference in pressure will be greater as theextraction tube is situated nearer the entrance to the coil.

When operating With steam at a higher pressure than the atmosphericpressure the most simple and economical method is often to l'eave thetrap serving as a deposit for the separated impurities slightly open atits upper part. In that way, the steam entrained by the extraction tubesis lest; but, since its proportion is insigneeds of the purification.

' The second improvement in the nificazt, that loss does not affect theeconomy of the process, whichis much simplified in that In industrieshaving multiple efect evaporators, as in sugar mills, for instance, theextraction traps for the impurities can be con-.

be employed. For example, if it is a question of A separating from astream of natural gas the naphthas or gasdlines it may contain, insteadof water there can be employed carbides of greater dennected With thecalandria of anevaporator in which the steam operates at a lowerpressure be interposed between the trap and the calandria.

When operating to purify a gaS-as, forinstance, coal gas, Which hascommercial value and Which it is not convenient to let Ioose intothe airby reason of the attending dangers; a:

loWer Will aspire the gas from the deposit chamber for the impuritiesand Will returnit to the entrance of the separ'ator, impelling itthrough a complementary separator whe1e its purification is elIecfited.This 'arrangement permits regulation of the. aspiration by means of thespeed of the blower in order to adapt it to the process is based uponthe desirability of enlarging the particles of very small sizeythat ingreat part form the im purities contained in the treated fluid, in ordertofacilitate their separation. The centrifugal force applied to theseimpurities is proporticnal to their mass, that is, to their' volume. Thegreatv er the volume the less, proportionally to that Volume, is theexterior surface of the. DarticleS, and in consequence the separatingmotion is much more easily eifected. l

The increase in volume of the particles of very small size foiming theimp'urities is accomplished by.bringing into the streamnew liquidscapable of being united.with said impuritis and of entraining them.Whenoperating upon steam, the most simple process consists in leavingthe consity than the naphthas, gas cil for instance. Such gas oil candissolve and carry along the liquide carbides and part of the gases thatthestream may contain; and such carbides Will be subsequently separatedfrom the same by distillation. 7 In a similar waymany industrial Wastescar-* ried by gaSesor by air can be recovered, treating such gases incentrifugal separators; in which separation cases it may be advantageousto in- -ject into such gases, previous to the separation operation orduring that operation, liquids capa ble of carrying or dissolving saidwastes.

effecting the extraction of the impurities through duit totally orpartially uncovered, thus bermitward the exterior of the section the'yconstitute something like a slight rain which goes through the stream oftreated steam, washing it. When instead of steam a gas is treated, coal'gas for instance the injection can consist of water, steam, or Watcrentrained by a stream of steam in the inanner of an injecter.

When the injection consists of steam, it is con venient tocool-theseparating coil subsequently in order to 'obtain total condensation orthe beabsorbed'by the following extraction tube. In-

steam, and sothat such condensation may faoili 7 tate the elimination orthe impurities in the trcated gas. In the particularcase of coal gas,the injection can also be made with Water whenthe gas. is at .a highte1hper.ture, the water be ing 'transformedinto steam and such steambeingf again liquefied subsequcntly by cooling before or duringtheseparation.

The separators themselves can preferably be adapted to the new process;for which, instead of tubes that are connected with the restrictedcollecting trough where such impurities have been inclosed, bycentrifugal force, such tubes may be the.prolongaticn of the outward endof the restricted trough, and the separator may be limited toth;remainder of the section at the place of conhectlon, By reason ofthis arrangement the section of the separator at the place of connectionThe separator can in that case be constri1cted with an original verydeep restricted trough and the depth is diminished at each point ofextraction by the subtraction of the Outer end of the restricted troughwhich is embodied in the extraction tube, so that at the end of theseparator said restricted trough disappear5 'entirely; or else,'therestricted trough can be made of small depth and be totally absorbed bythe first extraction tube, and subsequent to thatextraction the sectionof: the separator is gradually modified in a way to progressively createa new restricted trogh of the same' shape, Whih will, in turn,

te1mediate solutions between the two;extremes that have been pointedout, can alsofloe i1sed;

In the accdmpanying drawings:

Figurel representS the application of the separatOr to th purificationof the cils entrained by the exhaust steam of a. steam engine, which it.isdesired to employ in*heating a multiple 7 effect evaporating apparatusas in 'sugar mills.

' Figure 2 represents the application of the same separator to thepurification of a stream of gas. Figure3 represents another applicationof the same separator to the purification of a stream of gas. r v

Figures 4, 5 and 76 represent several advantageously applicable ways fortheconstruction of the separator in its attachment :tnthe extractiontubes.

Figure 7 shows in perspective and:oha largerscale a portion of aseparator coil With insulation along its outer peripheral section.

Referring to Figures 4, 5 and 6,jthey represent longitudinal sections ofthe separating .coil S at the place of, attachinent of an extractiontube E.

: In Figure 4 tube E 15 tangentially:attached without changing thesection ofthe separator,. In

Figure 5 tube E prolongs the'outward end of the impurities collectingrestricted trough while coi] S starts from the attachfl1entfiWith areduced Instead of 'water, otherliquids can sometimes section by reasonof-the subt1actiin of the outer.

end of the restricted collecting trough. This second arrangement has theadvantage of connecting the outer end of the restricted trough moredirectly with the extraction tube, and it prevents the expansion of thecirculating fiuid and the variation of its velocity, because the totalof the outfiow sections is equal to the coil section.

In the arrangement of Figure 4, on the contrary, the outflow sectionincreases slightly beyond the amount represented by the section of theextraction tube. In consequence this arrangement produces a slightexpansion of the gas, a slight decrease in its velocity and a slightmotion of the gas from the interior toward the exterior within the coilsection. This motion is evidently favorable to the separation.

It must be understood that the diiferences above pointed out between thefigures take it for granted that the velocity of the fiuid in tube E isequal to the velocity of the fluid in coil S; but it will be convenient,in practice, to increase the velocity in tube E and thus to create asuction increasing the efficiency of the separation.

Figure 6 represents an arrangement similar to that of Figure 5, with thedifference that the extraction tube E forms a small funnel at the pointof attachment, thus increasing the entrance section of the fiuid intothat tube at the expense of the section of the coi]. The correspondingcontraction of the separators section, followed by the expansion of thatsection toward the exterior, produces the phenomena pointed out inrelation to Figure 4 in a more prominent way than in the arrangementshown in that figure. Besides, the funnel facilitates notably theoutrance of all the fiiud contained in the outer extreme part of therestricted trough into the extraction tube.

The inconvenience of this arrangement consists in that it increases theresistance oifered by the separator to the motion of the fluid andresults a loss of pressure of 'said fiuid in its course through thecoil. Accordihg to the particular conditions of the separation to beaccomplished, one or another of those arrangements can prove to be moreadvantageous.

The arrangements mentioned can be applied to all the separationseffected by centrifugal separators, even if with less efiiciency ifthere does not exist in those separators a collecting restricted troughfor the impurities separated by centrifugal force. Particularly are theycapable of being applied to all the separations effected in theseparator of my Caban Patent No. 10,388 and they have been especiallystudied for that application. In consequence, they can also be indifferently applied to the separation cases represented in Figures 1, 2and 3, the first one being for purification of the exhaust steam of asteam engine by means of extraction of the cils it may entrain, on thesupposition that this exhaust steam is to be applied to the heating of amultiple effect evaporating apparatus as in sugar mills. The second andthird one for the purification of a stream of gas by means cf extractionof the tars, oils and water that it may carry in suspension.

Going back 130 Figure 1, the steam passes out of steam engins M throughtube V and enters tank Re which constitutes a chamber the function ofwhich is to lessen the variations that the intermlttent character of theengines exhaust would produce in velocity both in the separator and inthe tubing from the same. Upon passing out of said tank Re, the steamenters through tube A the separator S1 made up of three turns. Uponpassing out of such separator, the steam is conveyed by tube D to thecalandria of the first unit of the evaporating apparatus. In the figure,there has been interposed between the separator Si and the tube D asecond steam chamber R which it will generally be possible to omit.

The extraction tubes of the separator S1, 0, Cl and 02 convey to chamberR the impurities separated in the extreme exterior restricted trough ofsuch separator together with the steam surrounding them. Such streamsare united in tube B in order to enter chamber R vertically; and byreason of their inertia the impurities that are denser than the steamare precipitated against the bottom of tank R where they are united.Tank R contains a valve, actuated by a float in a well known way used insteam traps, so that When the impurities extracted from the steam reacha given level in chamber R said valve opens and empties out a good partof those impurities into the tank T. These impurities are thus emptiedout periodically from tank R into tank T; and they can be removed fromtank T in order to recover the oil they may contain. The steam enteringchamber R through tube B goes out of the same through the tube F whichconveys it through separator S2 and tube G to the calandria of thesecond unit of the multiple effect apparatus. Since that calandria isunder a notably 1ower pressure than the pressure of the separator, theregulation of the effect of such reduced pressure is efiected by meansof a valve (not shown) placed in tube G.

In the figure, tube F and the separator S2 have been drawn on a largerscale than the rest of the drawing in order to avoid toc smalldimensions that would make difficult the execution of the drawing andits understanding. In practice, the dimensions of the separator S2 willbe at least six times smaller than those of separator S1, and also thedimensions of the tube F, will hold about the same proportion to thoseof the tube D.

separator S2 can be of a greater number of turns than separator S1,although, in the figure, it only appears as made up of three turns. Itworks, according to the figure, without the diversion of any part of thestream of steam toward chamber R for depositing the impuritiesseparated. These impurities separated in said chamber keep filling thetube K situated at the bottom of that chamber and discharge. through a Ushape section into the tank J, situated at a lower level'sufficiently10W so that the difference in height compensates the vacuum existing inthe calandria of the second unit of the evaporating apparatus. By reasonof the height of chamber R, the impurities go out freely through tank Jfrom the moment at which tube K becornes nearly full.

My invention may also be applied to the second separator S2 byconnecting the'chamber R with the final condenser of the apparatus orwith the calandria of the third effect of such appa ratus.

The thermal insulation of the separator has not been shown in thefigure. If such insulation is not used, then the apparatus of the figurealso utilizes the second improvement of my invention by the productionof water condensation, thereby assisting in the entrainment of theimpurities contained in the steam. Also, as has been pointed out, suchthermal insulation can be limited to a part of the separator, leaving'Venti0nto the purification of a gas. 'enterg the separator S throughtube A. It then pref1ably vvithout insulation the sufiacenearer to thecenter of curvatura.

the fluidpath, and:the-resultirig droplets will solid particles.insulate thelast turn of the separator. Figure 2 represents theapplication of myinruns throughthe separator, which has been Thiswill"cause localized condensation adjacent the inner face of suchstreanis c, c", c and c coxmect b' means of tube E with tank R. Thestream purified in separator S2i5 conveyed by tube{F t chamberG where itis used to atomize, in atomizer P, the liquid to be injected into thestream shown with four turns, and goes out of the same through the tubeF. The streams of gas diverted' 'by extraction.tubes c, 01, 02 and caareunited in vertical tube B which conveys them to collection chamber R forimpurities.

A blower V draws the gas from chamberR and sends it to a secondseparator S. At .its exit 7 froin that seDarator the gas is conveyedthrough 'separator S convey the diverted streams and the separatedimpurities to tube Gwhich in turn leads them to the chamber R. v

atomized water into the treated gas, "whicheis effected by the tube I.The special arrangement atomization. V

In Figure 7 is shown *a portion of the helic0idal coil of a seriaratorS3 provided at its outer peripheral section'0jwith a heat insulating covIn said chamber the" impurities settle to the bottom, being of greaterdensity, and hence pass intermittentlyto tank T,

from which they are removed;

ering Q, while its inner peripheral section 01 a and which is joinedtosaid coil'at intervals by' means of branch pipes n connecting into saidinner coil face P. These branch pipesn extend in a direction to injectthe steam substantially tahgentially of the inner.fac of' the separatorCoil.

As the steam is injected in the inner face section P of the coil of theseparator S3, this steam Will condense, since said inner;face section isfree from insul.tion, andwill be projected by 'centrifugal forceacrosubstantiallythe entire section of the helicoidal passage defined bysaid coil S3 to Wash the gas and entrain impurities therein. 4

- 7 Figure 3 represents a second application of my 7 invention to thepurification of a gas.

The treat-' ed gas passes through tube A into separator S], is purifiedin the four turns 'of that sepa1ator and .goes out through tube M. Thestreams divertedfrom the gas through the extraction tubes ci, Cz, cg andcg are conveyd bytube B totank R:where the greater part of the:impurities that they may entrain are deposited, being. removed fromthat tank at intrVals and placed in tank T; Th suctionfrom tank R isproducedby,

blower C which irnpels' thegas through separator sz andtube F'to theentrance ofthe sepa;

of gas being treated in S1 and entering through tube H.

The arrangement shown in the figures 'deal' With specific cases; Whenthe case varies, those arrangements canalso vary. For example, in thepurification of an exhaust steam from a steam engins of lower pressurethan atmosph eric pressure, the separator will be situated be;tw eentheengine and the condenser; and the entrainment of thevapcrs that areto be separated Will be 61ected, either through the vacuum which mightbe caused by a small complementary condenser operated at a lowertemperature and'with a greater vacuum 'than the main condenser, 01- elseby forcing the diverted streams thrcugh their separator in the generalcondenser by' other purities diverted from the main stockare united Inthe installation represented by the figure, thesecond improvementbrought about by my invention in the application of'centrifgalpa-;rators is carried into practice by the injection of in order to be freejointly from the impurities they may entrain; But the first entrainingstream contains many more impurities than the second one; the secondonecontains more im- -purities thanthe third' one; and thus the successivediverted streams are each time purer.,

In Consequence it may be deemed more logical that each of those streamsbe purified separately,

thus preventing thatwhen'joining them in order to purify themjointly,'the' first of those streams contaminate the others.. Thisarrangement is the more logical as'the pressure at the connection of theextractio'n tube of the firstof the streams is higher thanat theconnectionof the second one; and in c0nsequcnce, While maintaining thesame Velocity, it permits the employnderit of a separator with a greaternumber of turns for the first diverted stream which is also more impure.

s The difierence of pressure existing between two successive connectionsis the greater the moi e:

distant those connection's'are. In consequehce,

' it Will be convenient in several cases to spacethe Connections so asto create a substantialdifference in pressure between the connections oftwo successive extraction tubes, and to purify each diyertedstreamseparately, applying to the purification of these streams asecondary separater proportionally larger the nearerthe eXtraG- mainSeparator,

The most convenient solution must be determined in accordance with thecase undercon-- sideration.

I have described -what I believe to be the best ,embodiments of myinvention. I do notwish,

however, to be confined to the embodinients shown but what I desire tocover by Letters Pat-- entis set forth in the appended claims. 7

1. Apparatus for the purification of a stream of gagwhich,ccmprisesa.helicoidal separaticn passage for the stream, having a -collection:channel of reduced diameter'extending along its outer side, arrariged,toreceiv' 'imprities imrator S1." The sucticn ofthestrerhs of gas thatis to the entranc of the pelled outwardly by centrifugal force and toform a fiuent stream carrying the impurities; a plurality of dischargepassages for impurities connected at spaced points With the channel; aseparator for gas and impurities connected to the discharge ends of saidwithdrawal passages; a purification device having an inlet connected tothe gas discharge from said separator, and a gas discharge from thepurification device discharging into the stream of gas passing throughthe separator.

2. Purification apparatus as set forth in claim 1 adapted for purifyingsteam in advance of a device utilizing steam at lower pressure, whichcomprises a discharge trap having an inlet connected to the impuritiesdischarge from the purification device and provided with a gas outletconnected to said lower pressure device.

3. Apparatus for the purification of a stream of gas which comprises ahelicoidal passage for the stream arranged to propel impurities in thestream by centrifugal force into the outer portion of the passage,discharge passages for the impurities connected to said outer portion atintervals, and a liquid atomizer discharging into the passage adjacentthe inner face thereof, the arrangement being such that the liquidparticles projected into the stream of gas in the passage are projectedoutwardly by centrifugal force across substantially the entire sectionof the passage to wash the gas and entrain impurities therein.

4. Purification apparatus as set forth in claim 3 in which the injectoris of the gas pressure operated type, and the gas is discharged into thehelicoidal passage.

5. Apparatus for the purification of a stream of gas which comprises ahelicoidal separating passage for the stream of gas arranged forpropulsion of impurities by centrifugal force toward the outer face ofthe path, discharge passages for the impurities and a portion of the gasconnected to said outer face at intervals, a separator for theimpurities and gas connected to said discharge passages, an injector ofwashing liquid discharging into the passage, a gas passage conmeeting agas outlet from the separator to the iniector, and a blower in the gaspassage arranged to withdraw the gas from the separator and to supplygas under pressure to the injector.

6. Apparatus for the purification of a stream of exhaust steam from asteam engine prior to introduction into a condenser operated at a higherVacuum than a steam engine condenser which comprises a helicoidalseparation passage for the stream arranged for propulsion of impuritiesby centrifugal force towards the outer face of the passage, a pluralityof discharge passages connected to said outer face at intervals, agravity separator for said impurities and entrapped steam connected tosaid passages, and a steam discharge passage connecting the steam outletof the separator With said higher Vacuum condenser, the arrangementbeing such that the latter condenser serves to draw the impurities andsteam from the separation passage.

7. Apparatus for the purification of a stream of exhaust steam from asteam engine prior to introduction into a condenser which comprises ahelicoidal separation passage for the stream arranged for propellingimpurities by centrifugal force towards the outer face of the passage; aplurality of discharge passages for impurities and entrapped steamconnected at intervals to the separation passage along said outer face;a

gravity separator for said steam and impurities connected to thedischarge passages, said separator having separate outlets for steam andimpurities; a steam discharge passage connecting the steam outlet of theseparator with the condenser, and a propelling device in the latterpassage arranged to force the steam from the separator into thecondenser.

8. Apparatus for the purification of engine exhaust steam for use inheating a multiple efiect evaporator, comprising a main helicoidalseparation passage for a current of said steam arranged for propulsionof impurities toward the outer face of the passage; a steam passageconnecting the discharge end of the main passage With the first effectof the evaporator; a plurality of discharge passages for impuritiesconnect ed to the separation passage along said outer face at intervals;a separator for impurities and steam connected to said impuritiesdischarge passages and having separate outlets for steamand impurities;an auxiliary helicoidal separation passage connected to the steam outletfrom the separator and discharging into a later operating effect of saidevaporator; a plurality of impurities discharge passages connected tothe auxiliary passage along its outer face, and a receiver forimpurities connected to the latter discharge passages.

9. Apparatus for the purification of engine exhaust steam for use inheating a multiple effect evaporator, comprising a main helicoidalseparation passage for a current of said steam, arranged to propelimpurities toward the outer face of the passage; a plurality ofdischarge passages for impurities connected at intervals to said passagealong its outer face; a separator for steam and impurities connected tosaid discharge passages and having separate outlets for steam andimpurities; a steam discharge passage connected to the steam outlet ofthe separator and discharging into said current of steam, said steamdischarge passage including an auxiliary helicoidal separation passagearranged to propel impurities toward the outer face of the passage; animpurities discharge passage connected to said outer face of theauxiliary helicoidal passage, and a steam propelling device located insaid steam discharge passage and generating steam discharge pressure atleast equal to the pressure of said steam current.

10. Purification apparatus as set forth in claim 9 including an injectorfor washing liquid discharging into the steam current in the mainhelicoidal passage, said injector being connected to said steamdischarge passage and operated by the steam under pressure from thelatter passage.

11. An apparatus for purifying a stream of gas which comprises ahelicoidal passage for the stream arranged to propel impurities in thestream by centrifugal force into the outer portion of the passage,discharge passages for the impurities connected to said outer portion atintervals, and a steam injection device for discharging steam into saidhelicoidal passage adjacent the inner face thereof, said inner facebeing free from insulation while the rst of the helicoidal passage isinsulated, whereby steam from said injection device is condensed in saidinner face and impelled therefrom by centrifugal force acrosssubstantially the entire section of said helicoidal passage to wash thegas and en trained impurities therein.

JEAN LOMIET ET LAVIGNE.

